🚀 go-pugleaf

>    If SunOS/4.0 does not have this option,

SunOS 4.0 has this option; I presume from your statement that you don't
have access to it.  In that case, also note that:

> Also, tell UNIX and Emacs that the Sun terminal supports 
>MULTI-Line and MULTI-Character insert/delete.

...the 4.0 "termcap" file has AL and DL capabilities for the "sun" entry
already, so you shouldn't add them.  (I don't know if later 3.x
"termcap" files had them; check before adding those entries.)